1. Field of the Invention
The invention relates to a field of microelectronic devices, and more particularly to a nonvolatile logic gate circuit based on phase change memories.
2. Description of the Related Art
Information storage and information processing are separated from each other in a traditional Von Neumann computer architecture, and memories for storing information communicate with processors for processing information via buses. However, with the advent of an era of Big Data, the so-called Von Neumann bottleneck, restraining further improvement of a computer's ability to process massive data in real time, still occurs in spite of continuous development of memories and processors, which means that neither information access speed of memories, nor information processing speed of processors, but limited data transmission speed of a bus connecting memories and processors restrains massive data transmission between memories and arithmetic units. The next generation of architecture and electronic devices combining information storage and processing is considered as an effective method for breaking through the bottleneck.
Current information processors are formed by logic gates of CMOS transistors as basic units, wherein data are processed based on logical level, and processed data are transmitted to and stored in special storage units such as internal memories and external memories. The logic gates, only capable of processing information while incapable of storing information, are inapplicable for future computer architecture combining storage and processing. Therefore, a nonvolatile logic gate circuit, capable of carrying out information processing such as Boolean logic operations and nonvolatile information storage, is required. A Chinese patent titled A Logic Gate Circuit Based on Memristors (application No. 201210234665.X, application date Jul. 9, 2012) discloses a device conducting logic operations based on nonvolatile change of resistance state of memristors. However, the circuit is inapplicable for large-scale production in market due to some unsolved problems concerning consistency and reliability of memristors, and current leakage and crosstalk in arrays.